The HSUS came into being because, for several years previously, a great many people throughout the United States were aware of the tremendous need for a strong humane group that would actively endorse and work towards eliminating, on a national scale, some of the more obvious cruelties and injustices imposed on animals in slaughterhouses and by uncontrolled breeding of domestic pets. They also realized the necessity for a humane organization that would act in a missionary role, to encourage and assist in the formation of humane societies in the thousands of towns and areas where none existed.
Parkes, Patrick B. and Sichel, Jacques V., "Twenty-Five Years of Growth & Achievement: The Humane Society of the United States (1954-1979)" (1979). Humane Societies and Rescue Organizations. 1.